[1,2,3]triazolo[4,5-D]pyrimidine derivatives

ABSTRACT

The invention relates to a compound of formula (I) 
                         
wherein R 1  to R 4  are defined as in the description and in the claims. The compound of formula (I) can be used as a medicament.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/EP2017/065037, filed on Jun. 20, 2017, which claims priority fromEuropean Patent Application No. 16175953.5 filed on Jun. 23, 2016, thecontents of which are incorporated herein by reference in theirentireties.

The present invention relates to novel [1,2,3]triazolo[4,5-d]pyrimidinederivatives with affinity for the type-2 cannabinoid (CB2) receptor, tothe preparation thereof and to the diagnostic and therapeutic usethereof.

The invention relates in particular to a compound of formula (I)

-   -   wherein    -   R¹ is a ring selected from phenyl, [1,2,5]oxadiazolyl, pyridinyl        and pyrimidinyl, wherein said ring is substituted with one        substituent selected from haloalkyldiazirenyl and        alkynyldiazirenylalkylaminocarbonyl and optionally further        substituted with halogen or cyano;    -   R² and R³ are independently selected from hydrogen, halogen and        hydroxyl; and    -   R⁴ is alkyl or phenylhaloalkyl;    -   or a pharmaceutically acceptable salt or ester thereof.

Novel [1,2,3]triazolo[4,5-d]pyrimidine derivatives that have highaffinity and great selectivity towards the cannabinoid CB2 receptor havebeen found. These compounds have a modulatory effect on the activity ofthe CB2 receptor. The term ‘modulatory effect’ especially means agonist,antagonist and/or inverse agonist effects.

Agonists of the Cannabinoid Receptor 2 are useful for therapy and/orprophylaxis in a mammal. The compound of formula (I) is particularlyuseful in the treatment or prophylaxis of e.g. pain, atherosclerosis,age-related macular degeneration, diabetic retinopathy, glaucoma,diabetes mellitus, inflammation, inflammatory bowel disease,ischemia-reperfusion injury, acute liver failure, liver fibrosis, lungfibrosis, kidney fibrosis, systemic fibrosis, acute allograft rejection,chronic allograft nephropathy, diabetic nephropathy,glomerulonephropathy, cardiomyopathy, heart failure, myocardialischemia/infarction, systemic sclerosis, thermal injury, burning,hypertrophic scars, keloids, gingivitis pyrexia, liver cirrhosis ortumors, regulation of bone mass, neurodegeneration, stroke, transientischemic attack or uveitis.

Inverse agonists of the Cannabinoid Receptor 2 are useful for therapyand/or prophylaxis in a mammal.

The compound of formula (I) is particularly useful in the treatment orprophylaxis of pain, neuropathic pain, asthma, osteoporosis,inflammation, psychiatric diseases, psychosis, oncology, encephalitis,malaria, allergy, immunological disorders, arthritis, gastrointestinaldisorders, psychiatric disorders rheumatoid arthritis, psychosis andallergy.

The cannabinoid receptors are a class of cell membrane receptorsbelonging to the G protein-coupled receptor superfamily. There arecurrently two known subtypes, termed Cannabinoid Receptor 1 (CB1) andCannabinoid Receptor 2 (CB2). The CB1 receptor is mainly expressed inthe central nervous (i.e. amygdala cerebellum, hippocampus) system andto a lesser amount in the periphery. CB2, which is encoded by the CNR2gene, is mostly expressed peripherally, on cells of the immune system,such as macrophages and T-cells (Ashton, J. C. et al. CurrNeuropharmacol 2007, 5(2), 73-80; Miller, A. M. et al. Br J Pharmacol2008, 153(2), 299-308; Centonze, D., et al. Curr Pharm Des 2008, 14(23),2370-42), and in the gastrointestinal system (Wright, K. L. et al. Br JPharmacol 2008, 153(2), 263-70). The CB2 receptor is also widelydistributed in the brain where it is found primarily on microglia andnot neurons (Cabral, G. A. et al. Br J Pharmacol 2008, 153(2): 240-51).

Modulators of the Cannabinoid Receptor 2 are useful for therapy and/orprophylaxis in a mammal.

The interest in CB2 receptor agonists has been steadily on the riseduring the last decade (currently 30-40 patent applications/year) due tothe fact that several of the early compounds have been shown to havebeneficial effects in pre-clinical models for a number of human diseasesincluding chronic pain (Beltramo, M. Mini Rev Med Chem 2009, 9(1),11-25), atherosclerosis (Mach, F. et al. J Neuroendocrinol 2008, 20Suppl 1, 53-7), regulation of bone mass (Bab, I. et al. Br J Pharmacol2008, 153(2), 182-8), neuroinflammation (Cabral, G. A. et al. J LeukocBiol 2005, 78(6), 1192-7), ischemia/reperfusion injury (Pacher, P. etal. Br J Pharmacol 2008, 153(2), 252-62), systemic fibrosis(Akhmetshina, A. et al. Arthritis Rheum 2009, 60(4), 1129-36;Garcia-Gonzalez, E. et al. Rheumatology (Oxford) 2009, 48(9), 1050-6),liver fibrosis (Julien, B. et al. Gastroenterology 2005, 128(3), 742-55;Munoz-Luque, J. et al. J Pharmacol Exp Ther 2008, 324(2), 475-83).

Ischemia/reperfusion (I/R) injury is the principal cause of tissuedamage occurring in conditions such as stroke, myocardial infarction,cardiopulmonary bypass and other vascular surgeries, and organtransplantation, as well as a major mechanism of end-organ damagecomplicating the course of circulatory shock of various etiologies. Allthese conditions are characterized by a disruption of normal bloodsupply resulting in an insufficient tissue oxygenation. Re-oxygenatione.g., reperfusion is the ultimate treatment to restore normal tissueoxygenation. However the absence of oxygen and nutrients from bloodcreates a condition in which the restoration of circulation results infurther tissue damage. The damage of reperfusion injury is due in partto the inflammatory response of damaged tissues. White blood cells,carried to the area by the newly returning blood, release a host ofinflammatory factors such as interleukins as well as free radicals inresponse to tissue damage. The restored blood flow reintroduces oxygenwithin cells that damages cellular proteins, DNA, and the plasmamembrane.

Remote ischemic preconditioning (RIPC) represents a strategy forharnessing the body's endogenous protective capabilities against theinjury incurred by ischemia and reperfusion. It describes the intriguingphenomenon in which transient non-lethal ischemia and reperfusion of oneorgan or tissue confers resistance to a subsequent episode of “lethal”ischemia reperfusion injury in a remote organ or tissue. The actualmechanism through which transient ischemia and reperfusion of an organor tissue confers protection is currently unknown although severalhypotheses have been proposed.

The humoral hypothesis proposes that the endogenous substance (such asadenosine, bradykinin, opioids, CGRP, endocannabinoids, Angiotensin I orsome other as yet unidentified humoral factor) generated in the remoteorgan or tissue enters the blood stream and activates its respectivereceptor in the target tissue and thereby recruiting the variousintracellular pathways of cardioprotection implicated inischemicpreconditioning.

Recent data indicates that endocannabinnoids and their receptors, inparticular CB2 might be involved in pre-conditioning and contribute toprevent reperfusion injury by downregulation of the inflammatoryresponse (Pacher, P. et al. Br J Pharmacol 2008, 153(2), 252-62).Specifically, recent studies using CB2 tool agonists demonstrated theefficacy of this concept for reducing the IR injury in the heart (Defer,N. et al. Faseb J 2009, 23(7), 2120-30), the brain (Zhang, M. et al. JCereb Blood Flow Metab 2007, 27(7), 1387-96), the liver (Batkai, S. etal. Faseb J 2007, 21(8), 1788-800) and the kidney (Feizi, A. et al. ExpToxicol Pathol 2008, 60(4-5), 405-10).

Moreover, over the last few years, a growing body of literatureindicates that CB2 can also be of interest in sub-chronic and chronicsetting. Specific upregulation of CB1 and CB2 has been shown to beassociated in animal models of chronic diseases associated with fibrosis(Garcia-Gonzalez, E. et al. Rheumatology (Oxford) 2009, 48(9), 1050-6;Yang, Y. Y. et al. Liver Int 2009, 29(5), 678-85) with a relevantexpression of CB2 in myofibroblasts, the cells responsible for fibrosisprogression.

Activation of CB2 receptor by selective CB2 agonist has in fact beenshown to exert anti-fibrotic effect in diffuse systemic sclerosis(Garcia-Gonzalez, E. et al. Rheumatology (Oxford) 2009, 48(9), 1050-6)and CB2 receptor has emerged as a critical target in experimental dermalfibrosis (Akhmetshina, A. et al. Arthritis Rheum 2009, 60(4), 1129-36)and in in liver pathophysiology, including fibrogenesis associated withchronic liver diseases (Lotersztajn, S. et al. Gastroenterol Clin Biol2007, 31(3), 255-8; Mallat, A. et al. Expert Opin Ther Targets 2007,11(3), 403-9; Lotersztajn, S. et al. Br J Pharmacol 2008, 153(2),286-9).

Inverse agonists of the Cannabinoid Receptor 2 are useful for therapyand/or prophylaxis in a mammal.

The compound of formula (I) is particularly useful in the treatment orprophylaxis of pain, neuropathic pain, asthma, osteoporosis,inflammation, psychiatric diseases, psychosis, oncology, encephalitis,malaria, allergy, immunological disorders, arthritis, gastrointestinaldisorders, psychiatric disorders rheumatoid arthritis, psychosis andallergy.

The interest in CB2 receptor ligands has been steadily on the riseduring the last decade (currently 30-40 patent applications/year).Evidence from different sources support the view that lipidendocannabinoid signaling through CB2 receptors represents an aspect ofthe mammalian protective armamentarium (Pacher, P. Prog Lipid Res 2011,50, 193). Its modulation by either selective CB2 receptor agonists orinverse agonists/antagonists (depending on the disease and its stage)holds unique therapeutic potential in a huge number of diseases. For CB2inverse agonists/antagonists therapeutic opportunities have beendemonstrated for many pathological conditions including pain (Pasquini,S. J Med Chem 2012, 55(11): 5391), neuropathic pain (Garcia-Gutierrez,M. S. Br J Pharmacol 2012, 165(4): 951), psychiatric disorders(Garcia-Gutierrez, M. S. Br J Pharmacol 2012, 165(4): 951), psychosis(Garcia-Gutierrez, M. S. Br J Pharmacol 2012, 165(4): 951), osteoporosisand inflammation (Sophocleous, A. Calcif Tissue Int 2008, 82(Suppl.1):Abst OC18), psychiatric diseases and psychosis (Garcia-Gutierrez, M.S. Br J Pharmacol 2012, 165(4): 951), oncology (Preet, A. Cancer PrevRes 2011, 4: 65), encephalitis and malaria (Zimmer, A. WO 2011045068),allergy and inflammation (Ueda, Y. Life Sci 2007, 80(5): 414),encephalitis and malaria (Zimmer, WO 2011045068), asthma (Lunn, C. A. JPharmacol Exp Ther 2006, 316(2): 780), immunological disorders(Fakhfouri, G. Neuropharmacology 2012, 63(4): 653), rheumatoid arthritis(Chackalamannil, S. U.S. Pat. No. 7,776,889), arthritis (Lunn, C. A. JPharmacol Exp Ther 2006, 316(2): 780), and gastrointestinal disorders(Barth, F. FR 2887550).

The compounds of the invention bind to and modulate the CB2 receptor andhave lower CB1 receptor activity.

The compounds of the invention contain a diazirin moiety which canoptionally be used to form a covalent bond with the CB2 receptor afterphotochemical activation. Such small organic molecules as covalentmodifiers can be used for the detection and localisation of the target,for imaging, and for therapeutic use (compare e.g. Adebayo A Adeniyi,Ramesh Muthusamy & Mahmoud ES Soliman, Expert Opin. Drug Discov. (2016)11(1):79-90).

In the present description the term “alkyl”, alone or in combination,signifies a straight-chain or branched-chain alkyl group with 1 to 8carbon atoms, particularly a straight or branched-chain alkyl group with1 to 6 carbon atoms and more particularly a straight or branched-chainalkyl group with 1 to 4 carbon atoms. Examples of straight-chain andbranched-chain C₁-C₈ alkyl groups are methyl, ethyl, propyl, isopropyl,butyl, isobutyl, tert.-butyl, the isomeric pentyls, the isomeric hexyls,the isomeric heptyls and the isomeric octyls, particularly methyl,ethyl, propyl, butyl and pentyl. Particular examples of alkyl aremethyl, ethyl and tert.-butyl.

The terms “halogen” or “halo”, alone or in combination, signifiesfluorine, chlorine, bromine or iodine and particularly fluorine,chlorine or bromine, more particularly fluorine and chlorine. The term“halo”, in combination with another group, denotes the substitution ofsaid group with at least one halogen, particularly substituted with oneto five halogens, particularly one to four halogens, i.e. one, two,three or four halogens.

The term “haloalkyl”, alone or in combination, denotes an alkyl groupsubstituted with at least one halogen, particularly substituted with oneto five halogens, particularly one to three halogens. Particular“haloalkyl” are trifluoromethyl and difluoromethyl.

The term “alkynyl”, alone or in combination, signifies a straight-chainor branched hydrocarbon residue comprising a carbon-carbon triple bondand from 2 and up to 8, preferably up to 6, particularly preferred up to4 carbon atoms. A particular example of alkynyl is 1-butynyl.

The terms “hydroxyl” and “hydroxy”, alone or in combination, signify the—OH group.

The term “oxy”, alone or in combination, signifies the —O— group.

The term “carbonyl”, alone or in combination, signifies the —C(O)—group.

The term “amino”, alone or in combination, signifies the primary aminogroup (—NH₂), the secondary amino group (—NH—), or the tertiary aminogroup (—N—).

The terms “diazirinyl” and “diazirenyl” are both used in the presentdescription to designate the group

The term “pharmaceutically acceptable salts” refers to those salts whichretain the biological effectiveness and properties of the free bases orfree acids, which are not biologically or otherwise undesirable. Thesalts are formed with inorganic acids such as hydrochloric acid,hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid,particularly hydrochloric acid, and organic acids such as acetic acid,propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid,malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid,benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid,ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid,N-acetylcystein. In addition these salts may be prepared form additionof an inorganic base or an organic base to the free acid. Salts derivedfrom an inorganic base include, but are not limited to, the sodium,potassium, lithium, ammonium, calcium, magnesium salts. Salts derivedfrom organic bases include, but are not limited to salts of primary,secondary, and tertiary amines, substituted amines including naturallyoccurring substituted amines, cyclic amines and basic ion exchangeresins, such as isopropylamine, trimethylamine, diethylamine,triethylamine, tripropylamine, ethanolamine, lysine, arginine,N-ethylpiperidine, piperidine, polyamine resins. The compound of formula(I) can also be present in the form of zwitterions. Particularlypreferred pharmaceutically acceptable salts of compounds of formula (I)are the salts of hydrochloric acid, hydrobromic acid, sulfuric acid,phosphoric acid and methanesulfonic acid.

“Pharmaceutically acceptable esters” means that compounds of generalformula (I) may be derivatised at functional groups to providederivatives which are capable of conversion back to the parent compoundsin vivo. Examples of such compounds include physiologically acceptableand metabolically labile ester derivatives, such as methoxymethylesters, methylthiomethyl esters and pivaloyloxymethyl esters.Additionally, any physiologically acceptable equivalents of thecompounds of general formula (I), similar to the metabolically labileesters, which are capable of producing the parent compounds of generalformula (I) in vivo, are within the scope of this invention.

If one of the starting materials or compounds of formula (I) contain oneor more functional groups which are not stable or are reactive under thereaction conditions of one or more reaction steps, appropriateprotecting groups (as described e.g. in “Protective Groups in OrganicChemistry” by T. W. Greene and P. G. M. Wuts, 3^(rd) Ed., 1999, Wiley,New York) can be introduced before the critical step applying methodswell known in the art. Such protecting groups can be removed at a laterstage of the synthesis using standard methods described in theliterature. Examples of protecting groups are tert-butoxycarbonyl (Boc),9-fluorenylmethyl carbamate (Fmoc), 2-trimethyl silylethyl carbamate(Teoc), carbobenzyloxy (Cbz) and p-methoxybenzyloxycarbonyl (Moz).

The compound of formula (I) can contain several asymmetric centers andcan be present in the form of optically pure enantiomers, mixtures ofenantiomers such as, for example, racemates, mixtures ofdiastereoisomers, diastereoisomeric racemates or mixtures ofdiastereoisomeric racemates.

The term “asymmetric carbon atom” means a carbon atom with fourdifferent substituents. According to the Cahn-Ingold-Prelog Conventionan asymmetric carbon atom can be of the “R” or “S” configuration.

The invention relates in particular to a compound of formula (I) wherein

-   R¹ is a ring selected from phenyl, [1,2,5]oxadiazolyl, pyridinyl and    pyrimidinyl, wherein said ring is substituted with one substituent    selected from haloalkyldiazirenyl and    alkynyldiazirenylalkylaminocarbonyl and optionally further    substituted with halogen;-   R² and R³ are independently selected from hydrogen, halogen and    hydroxyl; and-   R⁴ is alkyl or phenylhaloalkyl;-   or a pharmaceutically acceptable salt or ester thereof.

The invention further relates to:

A compound of formula (I) wherein R¹ is a ring selected from phenyl,[1,2,5]oxadiazolyl, pyridinyl and pyrimidinyl, wherein said ring issubstituted with one substituent selected from trifluoromethyldiazirenyland butynyldiazirenylethylaminocarbonyl and wherein said ring isoptionally further substituted with chlorine;

A compound of formula (I) wherein R¹ istrifluoromethyldiazirenyl(chloro)phenyl,butynyldiazirenylethylaminocarbonyl[1,2,5]oxadiazolyl,trifluoromethyldiazirenylphenyl, trifluoromethyldiazirenylpyridinyl ortrifluoromethyldiazirenylpyrimidinyl;

A compound of formula (I) wherein R¹ is [1,2,5]oxadiazolyl substitutedwith alkynyldiazirenylalkylaminocarbonyl;

A compound of formula (I) wherein R¹ isbutynyldiazirenylethylaminocarbonyl[1,2,5]oxadiazolyl;

A compound of formula (I) wherein R² and R³ are independently selectedfrom hydrogen, fluoro and hydroxyl;

A compound of formula (I) wherein R² and R³ are both halogen at the sametime;

A compound of formula (I) wherein R² and R³ are both fluoro at the sametime;

A compound of formula (I) wherein R⁴ is tert.-butyl orphenyldifluoromethyl;

A compound of formula (I) wherein R⁴ is tert.-butyl;

A compound of formula (I) wherein R¹ is a ring selected from phenyl,[1,2,5]oxadiazolyl, pyridinyl and pyrimidinyl, wherein said ring issubstituted with one substituent selected from trifluoromethyldiazirenyland butynyldiazirenylethylaminocarbonyl and wherein said ring isoptionally further substituted with chlorine or cyano;

A compound of formula (I) wherein R¹ istrifluoromethyldiazirenyl(chloro)phenyl,butynyldiazirenylethylaminocarbonyl[1,2,5]oxadiazolyl,trifluoromethyldiazirenylphenyl, trifluoromethyldiazirenylpyridinyl,trifluoromethyldiazirenylpyrimidinyl ortrifluoromethyldiazirenyl(cyano)phenyl; and

A compound of formula (I) wherein R² and R³ are both fluoro at the sametime, or one of R² and R³ is hydrogen and the other one is hydroxyl.

The invention further relates to a compound of formula (I) selected from

-   5-tert-butyl-2-({2-chloro-4-[3-(trifluoromethyl)-3H-diaziren-3-yl]phenyl}methyl)-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   4-{[5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-2-yl]methyl}-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide;-   4-({5-tert-butyl-7-[(3S)-3-hydroxypyrrolidin-1-yl]-2H-[1,2,3]triazolo[4,5-d]pyrimidin-2-yl}methyl)-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide;-   5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({2-[3-(trifluoromethyl)-3H-diaziren-3-yl]phenyl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   (3S)-1-[5-tert-butyl-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;-   5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   (3S)-1-{5-[difluoro(phenyl)methyl]-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl}pyrrolidin-3-ol;-   5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({4-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-3-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   (3S)-1-[5-tert-butyl-2-({4-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-3-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;-   5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-({4-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-3-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   (3S)-1-{5-[difluoro(phenyl)methyl]-2-({4-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-3-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl}pyrrolidin-3-ol;-   5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyrimidin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   (3S)-1-[5-tert-butyl-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyrimidin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;-   5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyrimidin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   (3S)-1-{5-[difluoro(phenyl)methyl]-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyrimidin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl}pyrrolidin-3-ol;-   5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   (3S)-1-[5-tert-butyl-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;-   5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   (3S)-1-{5-[difluoro(phenyl)methyl]-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl}pyrrolidin-3-ol;-   5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;-   5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidine;-   5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidine;-   (3S)-1-[5-tert-butyl-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;    and-   (3S)-1-[5-[difluoro(phenyl)methyl]-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol.

The invention further relates to a compound of formula (I) selected from

-   4-{[5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-2-yl]methyl}-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide;    and-   (3S)-1-[5-tert-butyl-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol.

The preparation of compounds of formula (I) of the present invention maybe carried out in sequential or convergent synthetic routes. Synthesesof the compounds of the invention are shown in the following scheme. Theskills required for carrying out the reactions and purifications of theresulting products are known to those skilled in the art. Thesubstituents and indices used in the following description of theprocesses have the significance given herein before unless indicated tothe contrary. In more detail, the compounds of formula (I) can bemanufactured by the methods given below, by the methods given in theexamples or by analogous methods. Appropriate reaction conditions forthe individual reaction steps are known to a person skilled in the art.Also, for reaction conditions described in literature affecting thedescribed reactions see for example: Comprehensive OrganicTransformations: A Guide to Functional Group Preparations, 2nd Edition,Richard C. Larock. John Wiley & Sons, New York, N.Y. 1999). We found itconvenient to carry out the reactions in the presence or absence of asolvent. There is no particular restriction on the nature of the solventto be employed, provided that it has no adverse effect on the reactionor the reagents involved and that it can dissolve the reagents, at leastto some extent. The described reactions can take place over a wide rangeof temperatures, and the precise reaction temperature is not critical tothe invention. It is convenient to carry out the described reactions ina temperature range between −78° C. to reflux. The time required for thereaction may also vary widely, depending on many factors, notably thereaction temperature and the nature of the reagents. However, a periodof from 0.5 hours to several days will usually suffice to yield thedescribed intermediates and compounds. The reaction sequence is notlimited to the one displayed in the schemes, however, depending on thestarting materials and their respective reactivity the sequence ofreaction steps can be freely altered. Starting materials are eithercommercially available or can be prepared by methods analogous to themethods given below, by methods described in references cited in thedescription or in the examples, or by methods known in the art.

a) Halides II are either commercially available or can be synthesizedaccording to methods known in the art. These halides II are convenientlyreacted with sodium azide in a suitable solvent such as acetonitrile,ethanol or DMF to afford azide derivatives III. Alternative preferredconditions involve the use of solvents like DMA, NMP or DMSO, even morepreferred are NMP and DMSO. In polar aprotic solvents like NMP and DMSO,the alkylations can usually be conducted at lower temperature than forexample in acetonitrile, often at room temperature to 40° C. (this isthe case for example for BnCl, 1-chloro-2-(chloromethyl)benzene orPMB-Cl; this depends of course on the reactivity of the halides II) andhence provide a better process safety window (caution organic azides areof course known to be potentially dangerous and process safety hasalways to be carefully assessed). The addition of water can bebeneficial as it increases the solubility of sodium azide and providedmore robust kinetic profiles as it helps to dissolves hard clumps ofNaN₃. It can also lead to a better filterability of the final azidereaction mixture. Filtration of the reaction mixture might be requiredfor example when the following cycloaddition is performed in acontinuous mode in small channels reactors. The azide is not isolatedand its solution is best introduced in the next step. This also avoidsits isolation which can also lead to safety issues.

b) Triazole derivatives IV can be prepared by a [2+3] cycloaddition ofazide derivatives III with 2-cyanoacetamide in the presence of anappropriate base such as sodium methoxide or sodium ethoxide in asuitable solvent such as methanol, ethanol or DMF. Alternative preferredconditions involve reacting the azide with 2-cyanoacetamide in solventslike NMP or DMSO, in the presence of sodium hydroxide. The batch processis usually performed at room temperature to 50° C., preferably betweenroom temperature and 40° C. (caution, process safety has always to becarefully assessed). The cycloaddition process is also amendable tocontinuous mode (for a relevant literature example, see Org. ProcessRes. Dev., 2009, 13 (6), pp 1401-1406) and in this case the reactiontemperature can be increased above 50° C., for example (but not limitedto) between 50° C. and 90° C., preferably between 60° C. and 70° C.

c) Triazole derivatives V can be obtained by acylation of IV with anacyl-halide in the presence of a base such as DIEA, DMAP, pyridine andthe like. Double acylation and the formation of nitrile side productshave been observed. These can be significant when working for example inpyridine as solvent. However, these can be minimized when using DMA orNMP, preferably DMA as solvent instead of pyridine. Preferred conditionsinvolves the use of 1.0-2 equiv. of pyridine and pivaloyl chloride,preferably 1.0 to 1.5 equiv., preferably around 1.5 equiv at 50-100° C.,preferably between 75-85° C. These high boiling polar solvents alsoallow telescoping the following cyclization step which greatlysimplifies the process.

d) Triazolopyrimidine derivatives VI can be prepared by intramolecularcyclization of triazole derivative V in the presence of a base such asKHCO₃, Na₂CO₃ and water either with or without a solvent such asmethanol, ethanol, dioxane and toluene. Alternative preferred conditionsinvolve the use of DMA or NMP as solvents, preferably DMA. The reactioncan be performed in the presence of KHCO₃ at 130-170° C., preferablybetween 140 and 160° C. Compound VI may exist as a tautomer or a mixtureof tautomers, for example:

Optionally amido amides IV can be reacted with nitriles R⁴—CN in thepresence of a base such as K₂CO₃ in a solvent such as DMF,preferentially at temperatures close to the boiling point of the solventto directly arrive at pyrimidones VI.

e) Chlorides VII can be obtained by reaction of VI with a chlorinationreagent such as POCl₃, SOCl₂ or (COCl)₂ in the presence of anappropriate base such as N,N-diethyl aniline, lutidine, or pyridine.Alternative preferred conditions involve the use of the Vilsmeierreagent as chlorinating agent. It can also be generated in situ byreacting oxalyl chloride with DMF. The chlorination can be performed forexample in acetonitrile, DCM or AcOEt, preferably in DCM. Theseconditions allow for mild reaction temperature and for example, avoidthe quench of excess POCl₃ upon work-up. The crude product can beintroduced in the next step.

f) Chlorides VII are conveniently reacted with amine nucleophiles in thepresence of an appropriate base such as trietylamine, DIEA or DBU in asuitable solvent such as acetonitrile, methanol, toluene or DMF to yieldtriazolo-pyrimidine derivatives VIII.

g) Deprotection of VIII is done under suitable conditions, in case ofPG=MPM under acidic conditions (TFA and the like), hydrogenation usingPd catalyst or oxidative cleavage (DDQ or CAN and the like) to yieldtriazolo-pyrimidines IX.

h) Triazole derivatives IX are conveniently reacted either with a halide(or sulfonate such as a mesylate, a nonaflate or a tosylate) in thepresence of suitable base such as DIEA, DBU, K₂CO₃, or Cs₂CO₃particularly Ag₂SO₄ in a solvent such as DMF, dioxane or toluene, oralternatively with an alcohol under Mitsunobu reaction conditions usinga suitable diazodicarboxylate (DEAD, DIAD and the like) and a phosphinesuch as PBu₃ or PPh₃ in an appropriate solvent such as THF, DCM ortoluene to afford final triazolo-pyrimidine derivatives I.

If one of the starting materials, acylation reagents used in step c),amines used in step f) or alkylation reagents used in step h), containsone or more functional groups which are not stable or are reactive underthe reaction conditions of one or more reaction steps, appropriateprotecting groups (P) (as described e.g. in T. W. Greene et al.,Protective Groups in Organic Chemistry, John Wiley and Sons Inc. NewYork 1999, 3^(rd) edition) can be introduced before the critical stepapplying methods well known in the art. Such protecting groups can beremoved at a later stage of the synthesis using standard methods knownin the art.

If one or more compounds of formulae II to IX, acylation reagents usedin step c), amines used in step f) or alkylation reagents used in steph), contain chiral centers, triazolopyrimidines of formula I can beobtained as mixtures of diastereomers or enantiomers, which can beseparated by methods well known in the art, e.g. (chiral) HPLC orcrystallization. Racemic compounds can e.g. be separated into theirantipodes via diastereomeric salts by crystallization or by separationof the antipodes by specific chromatographic methods using either achiral adsorbent or a chiral eluent.

The invention thus also relates to a process for the preparation of acompound of formula (I) comprising the reaction of a compound of formula(A)

in the presence of R¹—CH₂—X and a base, or in the presence of R¹—CH₂—OHunder Mitsunobu conditions, wherein R¹ to R⁴ are as defined above andwherein X is a leaving group.

Reaction conditions of step h) above can thus be used in the process ofthe invention.

Examples of leaving groups are halogen (e.g. chlorine or bromine),methanesulfonyl, para-toluenesulfonyl or —OSO₂(CF₂)₃CF₃.

A compound of formula (I) when manufactured according to a process ofthe invention is also an object of the invention.

Another embodiment of the invention provides a pharmaceuticalcomposition or medicament containing a compound of the invention and atherapeutically inert carrier, diluent or excipient, as well as a methodof using the compounds of the invention to prepare such composition andmedicament. In one example, the compound of formula (I) may beformulated by mixing at ambient temperature at the appropriate pH, andat the desired degree of purity, with physiologically acceptablecarriers, i.e., carriers that are non-toxic to recipients at the dosagesand concentrations employed into a galenical administration form. The pHof the formulation depends mainly on the particular use and theconcentration of compound, but preferably ranges anywhere from about 3to about 8. In one example, a compound of formula (I) is formulated inan acetate buffer, at pH 5. In another embodiment, the compound offormula (I) is sterile. The compound may be stored, for example, as asolid or amorphous composition, as a lyophilized formulation or as anaqueous solution.

Compositions are formulated, dosed, and administered in a fashionconsistent with good medical practice. Factors for consideration in thiscontext include the particular disorder being treated, the particularmammal being treated, the clinical condition of the individual patient,the cause of the disorder, the site of delivery of the agent, the methodof administration, the scheduling of administration, and other factorsknown to medical practitioners.

The compounds of the invention may be administered by any suitablemeans, including oral, topical (including buccal and sublingual),rectal, vaginal, transdermal, parenteral, subcutaneous, intraperitoneal,intrapulmonary, intradermal, intrathecal and epidural and intranasal,and, if desired for local treatment, intralesional administration.Parenteral infusions include intramuscular, intravenous, intraarterial,intraperitoneal, or subcutaneous administration.

The compounds of the present invention may be administered in anyconvenient administrative form, e.g., tablets, powders, capsules,solutions, dispersions, suspensions, syrups, sprays, suppositories,gels, emulsions, patches, etc. Such compositions may contain componentsconventional in pharmaceutical preparations, e.g., diluents, carriers,pH modifiers, sweeteners, bulking agents, and further active agents.

A typical formulation is prepared by mixing a compound of the presentinvention and a carrier or excipient. Suitable carriers and excipientsare well known to those skilled in the art and are described in detailin, e.g., Ansel, Howard C., et al., Ansel's Pharmaceutical Dosage Formsand Drug Delivery Systems. Philadelphia: Lippincott, Williams & Wilkins,2004; Gennaro, Alfonso R., et al. Remington: The Science and Practice ofPharmacy. Philadelphia: Lippincott, Williams & Wilkins, 2000; and Rowe,Raymond C. Handbook of Pharmaceutical Excipients. Chicago,Pharmaceutical Press, 2005. The formulations may also include one ormore buffers, stabilizing agents, surfactants, wetting agents,lubricating agents, emulsifiers, suspending agents, preservatives,antioxidants, opaquing agents, glidants, processing aids, colorants,sweeteners, perfuming agents, flavoring agents, diluents and other knownadditives to provide an elegant presentation of the drug (i.e., acompound of the present invention or pharmaceutical composition thereof)or aid in the manufacturing of the pharmaceutical product (i.e.,medicament).

The invention thus also relates to:

A compound of formula (I) for use as therapeutically active substance;

A pharmaceutical composition comprising a compound of formula (I) and atherapeutically inert carrier;

The use of a compound of formula (I) for the preparation of medicamentsfor the treatment or prophylaxis of pain, neuropathic pain,atherosclerosis, age-related macular degeneration, diabetic retinopathy,glaucoma, diabetes mellitus, inflammation, inflammatory bowel disease,ischemia-reperfusion injury, acute liver failure, liver fibrosis, lungfibrosis, kidney fibrosis, systemic fibrosis, acute allograft rejection,chronic allograft nephropathy, diabetic nephropathy,glomerulonephropathy, cardiomyopathy, heart failure, myocardialischemia/infarction, systemic sclerosis, thermal injury, burning,hypertrophic scars, keloids, gingivitis pyrexia, liver cirrhosis ortumors, regulation of bone mass, neurodegeneration, stroke, transientischemic attack, uveitis, asthma, osteoporosis, psychiatric diseases,psychosis, oncology, encephalitis, malaria, allergy, immunologicaldisorders, arthritis, gastrointestinal disorders, rheumatoid arthritisor allergy;

A compound of formula (I) for use in the treatment or prophylaxis ofpain, neuropathic pain, atherosclerosis, age-related maculardegeneration, diabetic retinopathy, glaucoma, diabetes mellitus,inflammation, inflammatory bowel disease, ischemia-reperfusion injury,acute liver failure, liver fibrosis, lung fibrosis, kidney fibrosis,systemic fibrosis, acute allograft rejection, chronic allograftnephropathy, diabetic nephropathy, glomerulonephropathy, cardiomyopathy,heart failure, myocardial ischemia/infarction, systemic sclerosis,thermal injury, burning, hypertrophic scars, keloids, gingivitispyrexia, liver cirrhosis or tumors, regulation of bone mass,neurodegeneration, stroke, transient ischemic attack, uveitis, asthma,osteoporosis, psychiatric diseases, psychosis, oncology, encephalitis,malaria, allergy, immunological disorders, arthritis, gastrointestinaldisorders, rheumatoid arthritis or allergy;

A method for the treatment or prophylaxis of pain, neuropathic pain,atherosclerosis, age-related macular degeneration, diabetic retinopathy,glaucoma, diabetes mellitus, inflammation, inflammatory bowel disease,ischemia-reperfusion injury, acute liver failure, liver fibrosis, lungfibrosis, kidney fibrosis, systemic fibrosis, acute allograft rejection,chronic allograft nephropathy, diabetic nephropathy,glomerulonephropathy, cardiomyopathy, heart failure, myocardialischemia/infarction, systemic sclerosis, thermal injury, burning,hypertrophic scars, keloids, gingivitis pyrexia, liver cirrhosis ortumors, regulation of bone mass, neurodegeneration, stroke, transientischemic attack, uveitis, asthma, osteoporosis, psychiatric diseases,psychosis, oncology, encephalitis, malaria, allergy, immunologicaldisorders, arthritis, gastrointestinal disorders, rheumatoid arthritisor allergy, which method comprises administering an effective amount ofa compound of formula (I) to a patient in need thereof; and

The use of a compound of formula (I) for the detection or the imaging ofthe CB2 receptor.

The invention will now be illustrated by the following examples whichhave no limiting character.

EXAMPLES Abbreviations

MS=mass spectrometry; CAN=ceric ammonium nitrate; CAN=chemical abstractservice number; Ac=acetyl; DIEA=N,N-diisopropylethylamine;DBU=1,8-Diazabicyclo[5.4.0]undec-7-ene; DMF=dimethylformamide;HPLC=LC=high performance liquid chromatography; HRMS=high resolutionmass spectrometry; MeCN=acetonitrile; NBS=N-Bromosuccinimide;NCS=N-Chloroosuccinimide; NMR data are reported in parts per million (6)relative to internal tetramethylsilane and are referenced to thedeuterium lock signal from the sample solvent (d₆-DMSO unless otherwisestated); coupling constants (J) are in Hertz; THF=tetrahydrofurane;TFA=trifluoroacetic acid; DCM=dichloromethane.

Example 15-tert-Butyl-2-({2-chloro-4-[3-(trifluoromethyl)-3H-diaziren-3-yl]phenyl}methyl)-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine

a) 1-(3-Chloro-4-methylphenyl)-2,2,2-trifluoroethanone

4-Bromo-2-chloro-1-methylbenzene (5.0 g, 24.3 mmol, 1.0 equiv) wasdissolved in THF (50 mL) and cooled to −78° C. BuLi (1.6 M in hexanes,17 mL, 27.2 mmol, 1.12 equiv) was added dropwise. After completion ofthe addition the reaction mixture was stirred for 30 min before2,2,2-trifluoro-N-methoxy-N-methylacetamide (4.0 g, 25.5 mmol, 1.05equiv) was added. The cooling bath was removed and it was stirred for 20minutes. The reaction was quenched by the addition of sat. aq. NH₄Cl andextracted with EtOAc. The combined organics were washed with aq. HCl (1M) and brine, dried over MgSO₄, filtered and concentrated. Flashchromatography on silica (20% Et₂O in pentane) afforded1-(3-chloro-4-methylphenyl)-2,2,2-trifluoroethanone (5.17 g, 23.2 mmol,95% yield) as yellow oil. ¹H NMR (300 MHz, Chloroform-d) δ=8.04 (s, 1H),7.89-7.83 (m, 1H), 7.45-7.39 (m, 1H), 2.49 (s, 3H).

b) 1-(3-Chloro-4-methylphenyl)-2,2,2-trifluoroethanone oxime

1-(3-Chloro-4-methylphenyl)-2,2,2-trifluoroethanone (3.67 g, 16.5 mmol,1.0 equiv) and hydroxylamine hydrochloride (1.20 g, 17.3 mmol, 1.05equiv) were combined with EtOH (32 mL). Pyridine (6.7 mL, 82 mmol, 5.0equiv) was added and the mixture was stirred at 70° C. overnight. Aftercooling to room temperature, water (200 mL) was added and the mix wasextracted with Et₂O. The combined organics were washed with HCl (aq. 0.5M) and brine. The organic phase was dried over MgSO₄, filtered andconcentrated. Flash chromatography on silica (10% EtOAc in hexanes)afforded 1-(3-chloro-4-methylphenyl)-2,2,2-trifluoroethanone oxime (3.45g, 14.5 mmol, 88% yield). ¹H NMR (400 MHz, Chloroform-d) δ=9.24 (s, 1H),7.58 (s, 1H), 7.35 (app s, 2H), 2.44 (s, 3H).

c) 1-(3-Chloro-4-methylphenyl)-2,2,2-trifluoroethanone O-tosyl oxime

1-(3-chloro-4-methylphenyl)-2,2,2-trifluoroethanone oxime (2.9 g, 12.2mmol, 1.0 equiv), NEt₃ (1.87 mL, 13.4 mmol, 1.1 equiv) and DMAP (149 mg,1.22 mmol, 0.1 equiv) were dissolved in CH₂Cl₂ (49 mL) and cooled to 0°C. Then a solution of TsCl (2.56 g, 13.4 mmol, 1.1 equiv) in CH₂Cl₂ (25mL) was added. Upon complete addition the cooling bath was removed andit was stirred at room temperature until TLC indicated completeconsumption of starting material. Water was added and the mix wasextracted with EtOAc. The organics were washed with brine, dried overMgSO₄, filtered and concentration. Flash chromatography on silica (10%Et₂O in pentane) afforded1-(3-chloro-4-methylphenyl)-2,2,2-trifluoroethanone O-tosyl oxime (3.9g, 9.95 mmol, 82% yield) as colorless solid. HRMS (ESI+) 392.0329(M+H⁺).

d) 3-(3-Chloro-4-methylphenyl)-3-(trifluoromethyl)-3H-diazirine

1-(3-Chloro-4-methylphenyl)-2,2,2-trifluoroethanone O-tosyl oxime (850mg, 2.17 mmol) was dissolved in Et₂O (30 mL) and cooled to −78° C.Ammonia (ca. 15 mL) was condensed into the flask and the reactionmixture was stirred overnight (thereby warmed to room temperature). Thereaction mix was filtered and the solids were washed with Et₂O. Thefiltrate was concentrated and purified by flash chromatography on silica(10% Et₂O in pentane) to give the intermediate diaziridine (464 mg, 1.96mmol, 90% yield). The intermediate was dissolved in Et₂O (10 mL) andAg₂O (858 mg, 3.7 mmol, 2.0 equiv) was added. After 15 min, the reactionmixture was filtered over celite and concentrated to afford3-(3-chloro-4-methylphenyl)-3-(trifluoromethyl)-3H-diazirine (410 mg,1.75 mmol, 94% yield) as yellow oil. ¹H NMR (400 MHz, Chloroform-d)δ=7.62-7.57 (m, 1H), 7.38-7.34 (m, 1H), 7.28-7.23 (m, 1H), 2.62 (s, 3H).

e) 3-(4-(Bromomethyl)-3-chlorophenyl)-3-(trifluoromethyl)-3H-diazirine

3-(3-Chloro-4-methylphenyl)-3-(trifluoromethyl)-3H-diazirine (365 mg,1.56 mmol, 1.00 equiv), benzoyl peroxide (23 mg, 0.10 mmol, 0.06 equiv)and NBS (731 mg, 4.11 mmol, 2.64 equiv) were combined with CCl₄ andheated to reflux until TLC indicated full consumption of the startingmaterial. Celite was added and the solvent was removed. Flashchromatography on silica afforded3-(4-(bromomethyl)-3-chlorophenyl)-3-(trifluoromethyl)-3H-diazirine (320mg, 1.02 mmol, 66% yield) as yellow oil. ¹H NMR (300 MHz, Chloroform-d)δ=7.48 (d, J=8.2, 1H), 7.23-7.18 (m, 1H), 7.09 (d, J=8.1, 1H), 4.56 (s,2H).

d)5-tert-Butyl-3-({2-chloro-4-[3-(trifluoromethyl)-3H-diaziren-3-yl]phenyl}methyl)-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine

5-tert-Butyl-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(CAS 1438465-59-8, 54 mg, 0.19 mmol, 1.0 equiv) and3-(4-(bromomethyl)-3-chlorophenyl)-3-(trifluoromethyl)-3H-diazirine (66mg, 0.21 mmol, 1.1 equiv) were dissolved in DMF (1 mL). DBU (38 μL, 0.25mmol, 1.3 equiv) was added and the reaction mix was for 30 min. The mixwas poured on water and extracted with EtOAc (3×). The organics werewashed with brine. The aqueous phase was extracted CH₂Cl₂. The combinedorganics were over MgSO₄, filtered and concentrated. Flashchromatography on silica (hex/DCM 1:1+0.5% MeOH) afforded5-tert-butyl-3-({2-chloro-4-[3-(trifluoromethyl)-3H-diaziren-3-yl]phenyl}methyl)-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(27 mg, 0.052 mmol, 27% yield) as slightly yellow wax. ¹H NMR (400 MHz,Chloroform-d) δ=7.25-7.20 (m, 2H), 7.08-7.04 (m, 1H), 5.92 (s, 2H),4.48-4.28 (m, 2H), 4.12 (dd, J=28.1, 15.2, 2H), 2.65-2.44 (m, 2H), 1.39(s, 9H).

Example 24-{[5-tert-Butyl-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-2-yl]methyl}-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide

a)N-(2-(3-(But-3-yn-1-yl)-3H-diazirin-3-yl)ethyl)-4-(hydroxymethyl)-1,2,5-oxadiazole-3-carboxamide

3-(But-3-ynyl)-3-(2-aminoethyl)-3H-diazirine (CAS 1450752-97-2, 96 mg,0.70 mmol, 1.0 equiv) was dissolved in toluene (2.3 mL) and cooled to 0°C. AlMe₃ (2 M in toluene, 370 μL, 0.74 mmol, 1.06 equiv) was addedslowly. After 30 min at 0° C., a solution6H-furo[3,4-c][1,2,5]oxadiazol-4-one (CAS 73314-58-6, 106 mg, 0.84 mmol,1.2 equiv) in toluene (1 mL) was added slowly. The cooling bath wasremoved and the mixture was stirred at room temperature for 1 h. Aprecipitate formed, THF (1 mL) was added and stirring was continued for1 h. The reaction was quenched by the addition of a sat. aq. solution ofRochelle's salt (2 mL) and water (2 mL). EtOAc (5 mL) was added and thereaction mix was vigorously stirred for 1 h. Extraction with EtOAc (3×5mL), washing with brine, drying over MgSO₄, filtration and concentrationfollowed by flash chromatography on silica (25% EtOAc in hexanes)affordedN-(2-(3-(but-3-yn-1-yl)-3H-diazirin-3-yl)ethyl)-4-(hydroxymethyl)-1,2,5-oxadiazole-3-carboxamide(171 mg, 0.65 mmol, 93% yield) as yellowish oil. HRMS (ESI+) 264.1096(M+H⁺).

b)(4-((2-(3-(But-3-yn-1-yl)-3H-diazirin-3-yl)ethyl)carbamoyl)-1,2,5-oxadiazol-3-yl)methylmethanesulfonate

N-(2-(3-(but-3-yn-1-yl)-3H-diazirin-3-yl)ethyl)-4-(hydroxymethyl)-1,2,5-oxadiazole-3-carboxamide(87 mg, 0.33 mmol, 1.0 equiv) and NEt₃ (69 μL, 0.50 mmol, 1.5 equiv)were dissolved in CH₂Cl₂ (1.1 mL) and cooled to 0° C. MsCl (31 μL, 0.40mmol, 1.2 equiv) was added. After 30 minutes, MeOH (0.1 mL) and celitewere added and the solvent was removed. Flash chromatography on silica(30% EtOAc in hexanes to 40% EtOAc in hexanes) afforded(4-((2-(3-(but-3-yn-1-yl)-3H-diazirin-3-yl)ethyl)carbamoyl)-1,2,5-oxadiazol-3-yl)methylmethanesulfonate (90 mg, 0.26 mmol, 80% yield) as colorless oil.

c)4-{[5-tert-Butyl-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]methyl}-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide

(4-((2-(3-(But-3-yn-1-yl)-3H-diazirin-3-yl)ethyl)carbamoyl)-1,2,5-oxadiazol-3-yl)methylmethanesulfonate (45 mg, 0.13 mmol, 1.0 equiv) and5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(CAS 1438465-59-8, 37 mg, 0.13 mmol, 1.0 equiv) were dissolved in DMF(0.44 mL) and NEt₃ (37 μL, 0.26 mmol, 2.0 equiv) was added. After 30min, EtOAc (30 mL) was added. It was washed with 5% aq. LiCl and brine,dried over MgSO₄ and concentrated. Flash chromatography on silicaafforded4-{[5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]methyl}-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide(12 mg, 0.023 mmol, 17% yield) as yellowish oil. HRMS (ESI+) 528.2387(M+H⁺).

Example 34-({5-tert-Butyl-7-[(3S)-3-hydroxypyrrolidin-1-yl]-2H-[1,2,3]triazolo[4,5-d]pyrimidin-2-yl}methyl)-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide

In analogy to the procedure described for the synthesis of4-{[5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl]methyl}-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide(example 2, step c) the title compound was prepared from(4-((2-(3-(but-3-yn-1-yl)-3H-diazirin-3-yl)ethyl)carbamoyl)-1,2,5-oxadiazol-3-yl)methylmethanesulfonate (40 mg, 0.12 mmol, 1.0 equiv) and(3S)-1-(5-tert-butyl-3H-triazolo[4,5-d]pyrimidin-7-yl)pyrrolidin-3-ol(CAS 1433946-74-7, 31 mg, 0.12 mmol, 1.0 equiv) and isolated as acolorless oil. HRMS (ESI+) 508.2524 (M+H⁺).

Example 45-[Difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidine

a) 2,6-Diiodobenzyl Alcohol

2,6-Diiodibenzoic acid (CAS 194084-84-9, 2.13 g, 5.35 mmol, 1.00 equiv)was suspended in CH₂Cl₂ (10.7 mL). DMF (3 drops) and oxalyl chloride(0.52 mL, 5.9 mmol, 1.1 equiv) were added. When bubbling ceased, thereaction mixture was heated to reflux for 30 minutes (TLC indicated fullconsumption of starting material). It was diluted with CH₂Cl₂, washedwith sat. aq. sodium bicarbonate and brine, dried over MgSO₄, filteredand concentrated. The crude acid chloride was dissolved in a 1:1 mixtureof MeCN and THF (30 mL). NaBH₄ (405 mg, 10.7 mmol, 2.00 equiv) was addedin portions at rt (exotherm). After 30 min TLC indicated full conversionof acid chloride. MeOH (5 mL) was added slowly and the resulting mixturewas diluted with water. Extraction with EtOAc (3×100 mL), washing withbrine (100 mL), drying over MgSO₄, filtration and concentration followedby flash chromatography on silica (15% EtOAc in hexanes to 20% to 50%)afforded the title compound as colorless solid (1.55 g, 4.31 mmol, 80%).HRMS (MALDI) 382.8399 (M+Na⁺).

b) 1,3-Diiodo-2-(((4-methoxybenzyl)oxy)methyl)benzene

2,6-Diiodobenzyl alcohol (1.61 g, 4.47 mmol, 1.00 equiv) was dissolvedin DMF and cooled to 0° C. NaH (60% in mineral oil, 215 mg, 5.37 mmol,1.20 equiv) was added and the mixture was stirred for 20 min.4-Methoxybenzyl chloride (0.67 mL, 4.9 mmol, 1.1 equiv) was added andthe cooling bath was removed. After 30 min, the reaction was quenched bythe addition of sat. aq. NH₄Cl (5 mL). The mix was extracted with EtOAc(3×50 mL). The combined organics were washed with 5% aq. LiCl (50 mL)and brine (50 mL), dried over MgSO₄, filtered and concentrated. Flashchromatography on silica (5% EtOAc in hexanes) afforded the titlecompound as colorless solid (1.9 g, 4.0 mmol, 88%). HRMS (MALDI)479.9078 (M⁺).

c)2,2,2-Trifluoro-1-(3-iodo-2-(((4-methoxybenzyl)oxy)methyl)phenyl)ethanone

1,3-Diiodo-2-(((4-methoxybenzyl)oxy)methyl)benzene (1.9 g, 4.0 mmol, 1.0equiv) was dissolved in THF (8 mL) and cooled to −30° C. A solution ofiPrMgCl.LiCl (0.87 M, 5.0 mL, 4.35 mmol, 1.10 equiv) was added and theresulting solution was stirred for 2.5 h, while the temperature wasallowed to rise to −20° C. N-methoxy-N-methyltrifluoroacetamide (0.68 g,4.4 mmol, 1.1 equiv) was added, the cooling bath was removed and thereaction was stirred overnight. Sat. aq. NH₄Cl was added and it wasextracted with EtOAc. The organics were washed with brine, dried overMgSO₄, filtered and concentrated. Flash chromatography on silicaafforded the title compound as colorless oil (1.04 g, 2.31 mmol, 58%).¹H NMR (400 MHz, CDCl₃) δ 7.95 (dd, J=7.9, 1.2 Hz, 1H), 7.35 (dd, J=7.6,1.0 Hz, 1H), 7.25 (d, J=8.1 Hz, 2H), 7.09 (t, J=7.8 Hz, 1H), 6.90 (d,J=8.7 Hz, 2H), 4.57 (s, 2H), 4.48 (s, 2H), 3.82 (s, 3H).

c)2,2,2-Trifluoro-1-(3-iodo-2-(((4-methoxybenzyl)oxy)methyl)phenyl)ethanoneoxime

2,2,2-Trifluoro-1-(3-iodo-2-(((4-methoxybenzyl)oxy)methyl)phenyl)ethanone(1.04 g, 2.31 mmol, 1.00 equiv) was combined with EtOH (4.6 mL),hydroxylamine hydrochloride (193 mg, 2.77 mmol, 1.20 equiv) and pyridine(0.28 mL, 3.5 mmol, 1.5 equiv). The mixture was heated at 80° C. untilTLC indicated full consumption of starting material. Concentration andflash chromatography on silica afforded the title compound (680 mg, 1.46mmol, 63%).

d)2,2,2-Trifluoro-1-(3-iodo-2-(((4-methoxybenzyl)oxy)methyl)phenyl)ethanoneO-tosyl oxime

2,2,2-Trifluoro-1-(3-iodo-2-(((4-methoxybenzyl)oxy)methyl)phenyl)ethanoneoxime (680 mg, 1.46 mmol, 1.00 equiv) was dissolved in CH₂Cl₂ (3 mL).TsCl (307 mg, 1.61 mmol, 1.10 equiv) and DMAP (18 mg, 0.15 mmol, 0.10equiv) were added and the mixture was stirred at rt. When TLC indicatedfull consumption of starting material, water was added. Extraction withCH₂Cl₂, washing with brine, drying over MgSO₄, filtration andconcentration followed by flash chromatography afforded the titlecompound as a 2:1 mixture of diastereomers (529 mg, 0.85 mmol, 58%).

e)3-(3-odo-2-(((4-methoxybenzyl)oxy)methyl)phenyl)-3-(trifluoromethyl)-3H-diazirine

2,2,2-Trifluoro-1-(3-iodo-2-(((4-methoxybenzyl)oxy)methyl)phenyl)ethanoneO-tosyl oxime (529 mg, 0.85 mmol, 1.00 equiv) was dissolved in Et₂O (6mL) and cooled to −78° C. Ammonia (ca. 6 mL) was then introduced and thereaction mix was stirred at reflux for 4 h. The cooling bath was removedand the volatiles were removed. The residue was suspended in diethylether and filtered. The filtrate was concentrated. MeOH (10 mL) wasadded and removed under reduced pressure (2×) to remove residualammonia. The residue was dissolved in MeOH (10 mL) and combined withNEt₃ (0.6 mL, 4.3 mmol, 5.0 equiv). The mixture was titrated with asolution of iodine in MeOH until a yellow-brown color persisted. The mixwas diluted with water (200 mL) and sat. aq. sodium thiosulfate (2 mL).Extraction with EtOAc (3×50 mL), washing with brine (50 mL), drying overMgSO₄, filtration and concentration followed by flash chromatography onsilica afforded the title compound as light-yellow oil (211 mg, 0.46mmol, 54%). ¹H NMR (300 MHz, CDCl₃) δ 7.97 (dt, J=8.0, 1.0 Hz, 1H), 7.65(d, J=7.7 Hz, 1H), 7.44-7.37 (m, 2H), 7.06 (td, J=7.8, 0.8 Hz, 1H),6.93-6.88 (m, 2H), 4.89 (s, 2H), 4.68 (s, 2H), 3.82 (d, J=0.8 Hz, 3H).

f) 3-(2-(((4-Methoxybenzyl)oxy)methyl)-3-((trimethylsilyl)ethynyl)phenyl)-3-(trifluoromethyl)-3H-diazirine

3-(3-odo-2-(((4-methoxybenzyl)oxy)methyl)phenyl)-3-(trifluoromethyl)-3H-diazirine(196 mg, 0.424 mmol, 1.00 equiv) was combined with DMF (1.4 mL, degassedby the freeze-pump-thaw method), PdCl₂(PPh₃)₂(30 mg, 0.042 mmol, 0.10equiv), CuI (16 mg, 0.085 mmol, 0.20 equiv) and NEt₃ (0.12 mL, 0.85mmol, 2.0 equiv). Trimethylsilylacetylene (89 μL, 0.64 mmol, 1.5 equiv)was added and the mixture was stirred at rt for 20 min. The reactionmixture was diluted with 5% aq. LiCl and extracted with diethyl ether.The organics were washed with 5% aq. LiCl and brine, dried over MgSO₄,filtered and concentrated. Flash chromatography on silica (2% EtOAc inhexanes) afforded the title compound as yellow oil (146 mg, 0.34 mmol,80%). HRMS (ESI⁺) 450.1819 (M+NH₄ ⁺).

g)3-(3-Ethynyl-2-(((4-methoxybenzyl)oxy)methyl)phenyl)-3-(trifluoromethyl)-3H-diazirine

3-(2-(((4-Methoxybenzyl)oxy)methyl)-3-((trimethylsilyl)ethynyl)phenyl)-3-(trifluoromethyl)-3H-diazirine (146 mg, 0.338mmol, 1.00 equiv) was dissolved in MeOH (1 mL) and K₂CO₃ (52 mg, 0.38mmol, 1.1 equiv) was added. After 1.5 h, sat. aq. NH₄Cl was added themixture was extracted with Et₂O (3×30 mL). The organics were washed withbrine, dried over MgSO₄, filtered and concentrated. Flash chromatographyon silica (3% EtOAc in hexanes) afforded the title compound as yellowoil. HRMS (ESI⁺) 383.0978 (M+Na⁺).

h) 2-Ethynyl-6-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzylmethanesulfonate

3-(3-Ethynyl-2-(((4-methoxybenzyl)oxy)methyl)phenyl)-3-(trifluoromethyl)-3H-diazirine(318 mg, 0.883 mmol, 1.00 equiv) combined with CH₂Cl₂ (8 mL) and H₂O(0.8 mL) at 0° C. DDQ (301 mg, 1.32 mmol, 1.50 equiv) was added and itwas stirred until TLC indicated full consumption of starting material.Sat. aq. sodium bicarbonate was added and the mix was extracted withCH₂Cl₂. The organics were dried over MgSO₄, filtered and concentrated.Filtration over a plug of silica (20% EtOAc in hexanes) afforded amixture of intermediate benzyl alcohol and p-anisaldehyde. The mixturewas dissolved in CH₂Cl₂ (8 mL) and cooled to 0° C. NEt₃ (0.18 mL, 1.3mmol, 1.5 equiv) was added followed by MsCl (76 μL, 0.97 mmol, 1.1equiv). After 20 min, the reaction was quenched by the addition of sat.aq. sodium bicarbonate, extracted with CH₂Cl₂, dried over MgSO₄,filtered and concentrated. Flash chromatography on silica (15% EtOAc inhexanes) afforded the title compound as colorless oil (244 mg, 0.767mmol, 87%). The material turned red upon standing and solidified in thefreezer. HRMS (ESI⁺) 341.0178 (M+Na⁺).

i)5-(Difluoro(phenyl)methyl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-7(4H)-one

In analogy to the procedure described for the synthesis of5-(difluoro(phenyl)methyl)-3-(2-(trifluoromethyl)benzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-7(4H)-one(example 2, step b) the title compound was prepared from5-amino-1-(4-methoxybenzyl)-1H-1,2,3-triazole-4-carboxamide (CAS133992-53-7, 2.0 g, 8.1 mmol, 1.0 equiv) and2,2-difluoro-2-phenylacetonitrile and isolated as colorless solid (2.0g, 5.2 mmol, 65%). ¹H NMR (400 MHz, DMSO) δ 13.57 (s, 1H), 7.75-7.66 (m,2H), 7.64-7.53 (m, 3H), 7.27 (d, J=8.4 Hz, 2H), 6.88 (d, J=8.2 Hz, 2H),5.64 (s, 2H), 3.72 (s, 3H).

j)7-Chloro-5-(difluoro(phenyl)methyl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine

In analogy to the procedure described for the synthesis of3-((5-(tert-Butyl)-7-chloro-3H-[1,2,3]triazolo[4,5-d]pyrimidin-3-yl)methyl)-4-methyl-1,2,5-oxadiazole(example 1, step a) the title compound was prepared from5-(Difluoro(phenyl)methyl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-7(4H)-oneand isolated as colorless solid (1.21 g, 3.01 mmol, 93%). HRMS (ESI⁺)402.0928 (M+H⁺).

k)5-(Difluoro(phenyl)methyl)-7-(3,3-difluoropyrrolidin-1-yl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine

In analogy to the procedure described for the synthesis of5-tert-butyl-3-[(4-methyl-1,2,5-oxadiazol-3-yl)methyl]-7-(1,2,5-triazaspiro[2.4]hept-1-en-5-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(example 1, step d) the title compound was prepared from7-chloro-5-(difluoro(phenyl)methyl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(622 mg, 1.55 mmol, 1.00 equiv) and 3,3-difluoropyrrolidinehydrochloride (244 mg, 1.70 mmol, 1.10 equiv) and isolated as colorlesssolid (600 mg, 1.27 mmol, 82%). HRMS (ESI⁺) 473.1707 (M+H⁺).

l)5-(Difluoro(phenyl)methyl)-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine

5-(Difluoro(phenyl)methyl)-7-(3,3-difluoropyrrolidin-1-yl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(200 mg. 0.423 mmol. 1.00 equiv) was combined with anisole (1.40 mL,12.8 mmol, 30.3 equiv) and trifluoroacetic acid (6.5 mL) and heated at65° C. for 5 h. After removal of the volatiles, the residue was taken upin EtOAc (50 mL) and washed with aq. NaOH (1 M, 3×10 mL). The aqueousphase was backextracted with EtOAc (2×20 mL). The combined organics werewashed with brine, dried over MgSO₄, filtered and concentrated. Flashchromatography on silica (50% EtOAc in hexanes to 100%) afforded productcontaminated with an unidentified byproduct. The solid was trituratedwith EtOH and filtered to leave a tan solid. The washings wereconcentrated and the residue was triturated with 20% EtOAc in hexanes.The suspension was filtered and the filtercake washed with the samesolvent mixture to give another crop of the product (74 mg in total,0.21 mmol, 50%). HRMS (ESI⁺) 353.1136 (M+H⁺).

m)5-[Difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidine

In analogy to the procedure described for the synthesis of5-tert-butyl-2-({2-chloro-4-[3-(trifluoromethyl)-3H-diaziren-3-yl]phenyl}methyl)-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine(example 1, step d) the title compound was prepared from5-(difluoro(phenyl)methyl)-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(23 mg, 0.065 mmol, 1.0 equiv) and2-ethynyl-6-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzylmethanesulfonate (27 mg, 0.085 mmol, 1.3 equiv) and isolated aslight-red oil (19 mg, 0.033 mmol, 51%). HRMS (ESI⁺) 575.1538 (M+H⁺).

Example 55-tert-Butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidine

5-tert-Butyl-7-(3,3-difluoropyrrolidin-1-yl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(CAS 1438465-59-8, 23 mg, 0.072 mmol, 1.0 equiv) and2-ethynyl-6-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzylmethanesulfonate (24 mg, 0.085 mmol, 1.2 equiv) were dissolved in DMF(0.5 mL). Trimethylamine (20 μL, 0.15 mmol, 2.0 equiv) was added and itwas stirred overnight at room temperature. The reaction mixture wasdiluted with EtOAc (60 mL), washed with 5% aq. LiCl (2×20 mL) and brine(1×20 mL), dried over MgSO₄, filtered and concentrated. Flashchromatography on silica (5% EtOAc in hexanes) afforded the titlecompound as colorless oil (13 mg, 0.026 mmol, 36%). HRMS (ESI⁺) 505.1882(M+H⁺).

Example 6(3S)-1-[5-tert-Butyl-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol

(3S)-1-(5-tert-Butyl-3H-triazolo[4,5-d]pyrimidin-7-yl)pyrrolidin-3-ol(23 mg, 0.088 mmol, 1.20 equiv) and2-ethynyl-6-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzylmethanesulfonate (23 mg, 0.072 mmol, 1.00 equiv) were dissolved in DMF(0.5 mL). Triethylamine (15 μL, 0.11 mmol, 1.5 equiv) was added and itwas stirred overnight. The reaction mixture was diluted with EtOAc (60mL), washed with 5% aq. LiCl (2×20 mL) and brine (1×20 mL), dried overMgSO₄, filtered and concentrated. The crude was purified by flashchromatography on silica (30% EtOAc in hexanes+5% AcOH). Fractionscontaining product were pooled, washed with sat. NaHCO₃ and brine, driedover MgSO₄, filtered and concentrated to yield the title compound ascolorless oil (10 mg, 0.021 mmol, 29%). HRMS (ESI⁺) 485.2015 (M+H⁺).

Example 7(3S)-1-[5-[Difluoro(phenyl)methyl]-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol

a)(S)-1-(5-(Difluoro(phenyl)methyl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl)pyrrolidin-3-ol

In analogy to the procedure described for the synthesis of5-(Difluoro(phenyl)methyl)-7-(3,3-difluoropyrrolidin-1-yl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(example 4, step k) the title compound was prepared from7-chloro-5-(difluoro(phenyl)methyl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidine(272 mg, 0.677 mmol, 1.00 equiv) and (S)-pyrrolidin-3-ol (65 mg, 0.75mmol, 1.1 equiv) and isolated as colorless foam (291 mg, 0.643 mmol,95%). HRMS (ESI⁺) 453.1850 (M+H⁺).

b)(S)-1-(5-(Difluoro(phenyl)methyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl)pyrrolidin-3-ol

(S)-1-(5-(Difluoro(phenyl)methyl)-3-(4-methoxybenzyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl)pyrrolidin-3-ol(141 mg, 0.312 mmol) was dissolved in trifluoroacetic acid (4.38 mL) andheated to 70° C. for 3 h. LCMS indicated the formation of product and ofthe respective trifluoroacetyl ester. After removal of the volatiles theresidue was dissolved in MeOH (3 mL) and THF (3 mL). K₂CO₃ (215 mg, 1.59mmol, 5.0 equiv) was added and it stirred for 30 minutes. LCMS indicatesmainly desired product and a small amount of both isomers of thestarting material, presumably due to non-selective reaction of thedesired product with benzyltrifluoroacetate as alkylating agent. Thereaction mix was neutralized with dilute HCl and concentrated. Flashchromatography on silica (5% MeOH in EtOAc to 10% to 30%) yielded acolorless solid (220 mg). The material was partitioned between EtOAc andsat. NaHCO₃. The aq. phase was removed. The organic phase was washedwith brine, dried over MgSO₄, filtered and concentrated to give thetitle compound as yellowish solid (69 mg, 0.21 mmol, 67%).

c)(3S)-1-[5-[Difluoro(phenyl)methyl]-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol

(S)-1-(5-(Difluoro(phenyl)methyl)-3H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl)pyrrolidin-3-ol(32 mg, 0.096 mmol, 1.0 equiv) and2-ethynyl-6-(3-(trifluoromethyl)-3H-diazirin-3-yl)benzylmethanesulfonate (31 mg, 0.097 mmol, 1.0 equiv) were dissolved in DMF(0.5 mL). DIPEA (25 μL, 0.15 mmol, 1.5 equiv) was added and the mixturewas stirred overnight at room temperature. The reaction mixture wasdiluted with EtOAc (50 mL), washed with 5% aq. LiCl (2×20 mL) and brine(1×20 mL), dried over MgSO₄, filtered and concentrated. Preparative TLC(20% EtOAc in hexanes+20% AcOH) afforded the title compound as colorlesswax (24 mg, 0.043 mmol, 45%). HRMS (ESI⁺) 555.1677 (M+H⁺).

Example 8

Pharmacological Tests

The following tests were carried out in order to determine the activityof the compounds of formula (I):

Radioligand Binding Assay

The affinity of the compounds of the invention for cannabinoid receptorswas determined using recommended amounts of membrane preparations(PerkinElmer) of human embryonic kidney (HEK) cells expressing the humanCNR1 or CNR2 receptors in conjunction with 1.5 or 2.6 nM [3H]-CP-55,940(Perkin Elmer) as radioligand, respectively. Binding was performed inbinding buffer (50 mM Tris, 5 mM MgCl₂, 2.5 mM EDTA, and 0.5% (wt/vol)fatty acid free BSA, pH 7.4 for CB1 receptor and 50 mM Tris, 5 mM MgCl₂,2.5 mM EGTA, and 0.1% (wt/vol) fatty acid free BSA, pH 7.4 for CB2receptor) in a total volume of 0.2 mL for 1 h at 30° C. shaking. Thereaction was terminated by rapid filtration through microfiltrationplates coated with 0.5% polyethylenimine (UniFilter GF/B filter plate;Packard). Bound radioactivity was analyzed for Ki using nonlinearregression analysis (Activity Base, ID Business Solution, Limited), withthe Kd values for [³H]CP55,940 determined from saturation experiments.The compounds of formula (I) show an excellent affinity for the CB2receptor with affinities below 10 μM, more particularly of 1 nM to 3 μMand most particularly of 1 nM to 100 nM.

The compounds according to formula (I) have an activity in the aboveassay (Ki) particularly of 0.5 nM to 10 μM, more particularly of 0.5 nMto 3 μM and most particularly of 0.5 nM to 100 nM.

All compounds are CB2 binders with Ki values below 3 uM and selectivityversus CB1 in the corresponding assay of at least 4 fold.

human CB2 Ki human CB1 Ki Example [μM] [μM] 1 2.3439 >10.000 20.9325 >10.000 3 2.8611 >10.000 4 1.0738 >10.000 5 0.0814 0.583 60.0992 >10.000 7 0.3579 5.459

cAMP Assay

CHO cells expressing human CB1 or CB2 receptors are seeded 17-24 hoursprior to the experiment 50.000 cells per well in a black 96 well platewith flat clear bottom (Corning Costar #3904) in DMEM (Invitrogen No.31331), 1× HT supplement, with 10% fetal calf serum and incubated at 5%CO₂ and 37° C. in a humidified incubator. The growth medium wasexchanged with Krebs Ringer Bicarbonate buffer with 1 mM IBMX andincubated at 30° C. for 30 min. Compounds were added to a final assayvolume of 100 μL and incubated for 30 min at 30° C. Using thecAMP-Nano-TRF detection kit the assay (Roche Diagnostics) was stopped bythe addition of 50 μL lysis reagent (Tris, NaCl, 1.5% Triton X100, 2.5%NP40, 10% NaN₃) and 50 μL detection solutions (20 μM mAb Alexa700-cAMP1:1, and 48 μM Ruthenium-2-AHA-cAMP) and shaken for 2 h at roomtemperature. The time-resolved energy transfer is measured by a TRFreader (Evotec Technologies GmbH), equipped with a ND:YAG laser asexcitation source. The plate is measured twice with the excitation at355 nm and at the emission with a delay of 100 ns and a gate of 100 ns,total exposure time 10 s at 730 (bandwidth 30 nm) or 645 nm (bandwidth75 nm), respectively. The FRET signal is calculated as follows:FRET=T730-Alexa730-P(T645-B645) with P=Ru730-B730/Ru645-B645, where T730is the test well measured at 730 nM, T645 is the test well measured at645 nm, B730 and B645 are the buffer controls at 730 nm and 645 nm,respectively. cAMP content is determined from the function of a standardcurve spanning from 10 μM to 0.13 nM cAMP.

EC₅₀ values were determined using Activity Base analysis (ID BusinessSolution, Limited). The EC₅₀ values for a wide range of cannabinoidagonists generated from this assay were in agreement with the valuespublished in the scientific literature.

β-Arrestin Translocation Assay-PathHunter™ (DiscoveRx)

PathHunter™ 3-arrestin CHO-K1 CNR1 cell line (catalog number #93-0200C2)and the β-arrestin CHO-K1 CNR2 cell line (catalog number #93-0706C2)were purchased from DiscoveRx Corporation. The cell line was engineeredto express the 3-galactosidase EA fragment fused to β-arrestin and theProLink complementary peptide fused to the target receptor. ThePathHunter™ protein complementation assay (DiscoveRx Corporation#93-0001) was performed according to the manufacturer's protocol. Assayplates were seeded containing 7500 (CNR1) and 10000 (CNR2) cells in 384well plates (Corning Costar #3707, white, clear bottom) in 20 μL cellplating reagent 2 (Discoverx #93-0563R2A). After incubation at 37° C.(5% CO₂, 95% relative humidity) overnight, 5 μL of test compound wasadded (1% final DMSO concentration) and the incubation continued at 30°C. for 90 min. Detection reagent (12 μL) was then added and theincubation continued at room temperature for 60 min. Plates were thenanalyzed for a chemiluminescent signal using a Victor ³V reader (PerkinElmer).

Example A

Film coated tablets containing the following ingredients can bemanufactured in a conventional manner:

Ingredients Per tablet Kernel: Compound of formula (I)  10.0 mg 200.0 mgMicrocrystalline cellulose  23.5 mg  43.5 mg Lactose hydrous  60.0 mg 70.0 mg Povidone K30  12.5 mg  15.0 mg Sodium starch glycolate  12.5 mg 17.0 mg Magnesium stearate  1.5 mg  4.5 mg (Kernel Weight) 120.0 mg350.0 mg Film Coat: Hydroxypropyl methyl cellulose  3.5 mg  7.0 mgPolyethylene glycol 6000  0.8 mg  1.6 mg Talc  1.3 mg  2.6 mg Iron oxide(yellow)  0.8 mg  1.6 mg Titan dioxide  0.8 mg  1.6 mg

The active ingredient is sieved and mixed with microcrystallinecellulose and the mixture is granulated with a solution ofpolyvinylpyrrolidone in water. The granulate is then mixed with sodiumstarch glycolate and magnesium stearate and compressed to yield kernelsof 120 or 350 mg respectively. The kernels are lacquered with an aq.solution/suspension of the above mentioned film coat.

Example B

Capsules containing the following ingredients can be manufactured in aconventional manner:

Ingredients Per capsule Compound of formula (I)  25.0 mg Lactose 150.0mg Maize starch  20.0 mg Talc  5.0 mg

The components are sieved and mixed and filled into capsules of size 2.

Example C

Injection solutions can have the following composition:

Compound of formula (I)  3.0 mg Polyethylene glycol 400 150.0 mg Aceticacid q.s. ad pH 5.0 Water for injection solutions ad 1.0 ml

The active ingredient is dissolved in a mixture of Polyethylene glycol400 and water for injection (part). The pH is adjusted to 5.0 byaddition of acetic acid. The volume is adjusted to 1.0 ml by addition ofthe residual amount of water. The solution is filtered, filled intovials using an appropriate overage and sterilized.

The invention claimed is:
 1. A compound of formula (I)

wherein R¹ is a ring selected from phenyl, [1,2,5]oxadiazolyl, pyridinyland pyrimidinyl, wherein said ring is substituted with one substituentselected from haloalkyldiazirenyl andalkynyldiazirenylalkylaminocarbonyl and optionally further substitutedwith halogen or cyano; R² and R³ are independently selected fromhydrogen, halogen and hydroxyl; and R⁴ is alkyl or phenylhaloalkyl; or apharmaceutically acceptable salt or ester thereof.
 2. The compoundaccording to claim 1, wherein R¹ is a ring selected from phenyl,[1,2,5]oxadiazolyl, pyridinyl and pyrimidinyl, wherein said ring issubstituted with one substituent selected from trifluoromethyldiazirenyland butynyldiazirenylethylaminocarbonyl and wherein said ring isoptionally further substituted with chlorine or cyano.
 3. The compoundaccording to claim 1, wherein R¹ istrifluoromethyldiazirenyl(chloro)phenyl,butynyldiazirenylethylaminocarbonyl[1,2,5]oxadiazolyl,trifluoromethyldiazirenylphenyl, trifluoromethyldiazirenylpyridinyl,trifluoromethyldiazirenylpyrimidinyl ortrifluoromethyldiazirenyl(cyano)phenyl.
 4. The compound according toclaim 1, wherein R¹ isbutynyldiazirenylethylaminocarbonyl[1,2,5]oxadiazolyl.
 5. The compoundaccording to claim 1, wherein R² and R³ are independently selected fromhydrogen, fluoro and hydroxyl.
 6. The compound according to claim 1,wherein R² and R³ are both fluoro, or one of R² and R³ is hydrogen andthe other one is hydroxyl.
 7. The compound according to claim 1, whereinR⁴ is tert-butyl or phenyldifluoromethyl.
 8. The compound according toclaim 1, wherein R⁴ is tert-butyl.
 9. The compound according to claim 1selected from the group consisting of:5-tert-butyl-2-({2-chloro-4-[3-(trifluoromethyl)-3H-diaziren-3-yl]phenyl}methyl)-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;4-{[5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-2-yl]methyl}-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide;4-({5-tert-butyl-7-[(3S)-3-hydroxypyrrolidin-1-yl]-2H-[1,2,3]triazolo[4,5-d]pyrimidin-2-yl}methyl)-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide;5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({2-[3-(trifluoromethyl)-3H-diaziren-3-yl]phenyl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;(3S)-1-[5-tert-butyl-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;(3S)-1-{5-[difluoro(phenyl)methyl]-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl}pyrrolidin-3-ol;5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({4-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-3-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;(3S)-1-[5-tert-butyl-2-({4-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-3-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-({4-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-3-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;(3S)-1-{5-[difluoro(phenyl)methyl]-2-({4-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-3-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl}pyrrolidin-3-ol;5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyrimidin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;(3S)-1-[5-tert-butyl-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyrimidin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyrimidin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;(3S)-1-{5-[difluoro(phenyl)methyl]-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyrimidin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl}pyrrolidin-3-ol;5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;(3S)-1-[5-tert-butyl-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;(3S)-1-{5-[difluoro(phenyl)methyl]-2-({3-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-4-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-7-yl}pyrrolidin-3-ol;5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-({5-[3-(trifluoromethyl)-3H-diaziren-3-yl]pyridin-2-yl}methyl)-2H-[1,2,3]triazolo[4,5-d]pyrimidine;5-[difluoro(phenyl)methyl]-7-(3,3-difluoropyrrolidin-1-yl)-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidine;5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidine;(3S)-1-[5-tert-butyl-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;and(3S)-1-[5-[difluoro(phenyl)methyl]-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;or a pharmaceutically acceptable salt thereof.
 10. The compoundaccording to claim 1 selected from the group consisting of:4-{[5-tert-butyl-7-(3,3-difluoropyrrolidin-1-yl)-2H-[1,2,3]triazolo[4,5-d]pyrimidin-2-yl]methyl}-N-{2-[3-(but-3-yn-1-yl)-3H-diaziren-3-yl]ethyl}-1,2,5-oxadiazole-3-carboxamide;and(3S)-1-[5-tert-butyl-2-[[2-ethynyl-6-[3-(trifluoromethyl)diazirin-3-yl]phenyl]methyl]triazolo[4,5-d]pyrimidin-7-yl]pyrrolidin-3-ol;or a pharmaceutically acceptable salt thereof.
 11. A process for themanufacture of a compound according to claim 1 comprising the reactionof a compound of formula (A)

in the presence of R¹—CH₂—X and a base, or in the presence of R¹—CH₂—OHunder Mitsunobu conditions, wherein R¹ to R⁴ are as defined in claim 1and wherein X is a leaving group.
 12. A compound manufactured accordingto the process of claim
 11. 13. A pharmaceutical composition comprisinga compound of claim 1, or a pharmaceutically acceptable salt or esterthereof, and a therapeutically inert carrier.
 14. A method for thetreatment of pain, which method comprises administering an effectiveamount of a compound of claim 1, or a pharmaceutically acceptable saltor ester thereof, to a patient in need thereof.
 15. The compoundaccording to claim 4, wherein R² and R³ are both fluoro, or one of R²and R³ is hydrogen and the other one is hydroxyl.
 16. The compoundaccording to claim 15, wherein R⁴ is tert-butyl.
 17. The method of claim14, wherein the pain is a neuropathic pain.